FCC Station Class Codes

Station class codes describe the purpose for which a particlular station is used. The most common ones are:

• FB - Base Station - A station at a specified site authorized to communicate with mobile stations.
• MO - Mobile Station - A station in the mobile service intended to be used while in motion or during halts at unspecified points. This includes hand carried transmitters and, with certain limitations, may also include boats and aircraft.
• FB2 - Mobile Relay - A repeater.
• FX1 - Control Station - A base station that operates through a repeater in the same way as a mobile station.
• FXO - Operational Fixed Station - A transceiver which may operate as a link between two or more fixed locations. The designator is often used in radio link or SCADA telemetry systems.
• FB4 - Community Repeater - A conventional repeater which is usually stand-alone (no connection to other sites or repeaters) and operates multiple CTCSS or CDCSS tones, or possibly a single-frequency LTR repeater which accommodates multiple subscribers. These subscribers need to be licensed individually to use their respective tone, code, or LTR talkgroup.
• FB6 - Private Carrier (profit) - A repeater operated by a radio communications provider for multiple subscribers who are covered under the carrier's license.
• FB7 - Private Carrier (non-profit) - A repeater operated by a not-for-profit entity for multiple subscribers who are covered under the entity's license.
• FB8 - Centralized Trunk Relay - A repeater operating within a centralized trunked radio system which has exclusive use of the designated frequency within a given geographic area. The designation is used between 150 - 512 MHz and may indicate a variety of technologies including analog, P25, 2-slot DMR (MOTOTRBO), NXDN, or other centralized trunking scheme. The use of FB8 on T-Band is seen, but is redundant, as T-Band systems which meet channel loading criteria already have geographic exclusivity. A T-Band trunked system should rather use FB2 instead, with trunking operation indicated as a YW in the Radio Service field.
• MO8 - Trunked Subscriber Unit - A mobile or hand-held transceiver operating in a centralized trunked radio system within an exclusive geographic area. This designation is used between 150 - 512 MHz to indicate that the frequency corresponds to an exclusive trunked system.

• Interconnect - A connection to the telephone network to allow radio users to make or receive telephone calls. Also called a phone patch. These stations are usually indicated by a "C" appended to the station class code.
• Itinerant - A station that is operated temporarily at different locations. These stations are usually indicated by an "I" appended to the station class code.

*FXO or FXB on 4.9 GHz?

4.9 GHz systems installed at permanent locations must be licensed to the particular sites they will be used at. In FCC 09-29, the Commission afforded priority to 4.9 GHz systems carrying broadband data versus those that did not. To differentiate primary or secondary status, in DA 09-2530, the Commission retasked the station class code FXB to indicate "broadband" and primary status. The legacy code, FXO now indicates secondary status for 4.9 GHz links only. This primary/secondary status for broadband does not apply to any other frequency band or use. Broadband can practically be carrying VoIP E9-1-1 and Computer Aided Dispatch traffic to and from remote PSAPs, or can be supplying transport to and from future generation LTE eNode-B stations. Discrete voice radio traffic itself does not fit the Commission's "broadband" qualifier, but radio traffic digitized and multiplexed into other data can.

Related Links

Sources:

• http://wireless.fcc.gov/uls/data/documentation/pa_codes24.txt
• 47CFR87.171 Class of station symbols (for aviation services)
• Emission Designator
• Radio Service Codes
• [1] FCC 09-29
• [2] DA 09-2530